We consider the reasons underlying clozapine withdrawal in a group of hospitalised schizophrenic inpatients and review clinical outcome following clozapine withdrawal. A retrospective case note study was undertaken of all patients (n=41) registered at the State Hospital, Carstairs, with the Clozaril Patient Monitoring Service between 1990 and 2001 whose clozapine therapy had either been withdrawn or never initiated following registration. Twelve patients refused to commence clozapine following registration: twenty-nine patients were subsequently studied. Thirteen patients stopped clozapine owing to non-compliance, whereas seven had clozapine withdrawn due to a clinically inadequate response. Eleven patients were withdrawn primarily because of an unacceptable side-effect burden, although only four had a 'red alert'. In twenty patients, abrupt clozapine withdrawal resulted in a marked, immediate deterioration in their mental state. Twenty-three patients remained at the State Hospital at a mean follow-up period of 75 months. The study highlights the relevance of psychoeducation for clozapine patients in the maintenance phase of treatment, the importance of minimising the side-effect burden by clozapine monotherapy, the effectiveness of clozapine serum level monitoring and the evidence base for adjuvant treatment.